EcoPlus® Hydrovescent Air Disc® air diffusers are great for aerating or circulating nutrients in your tanks or reservoirs. These air diffusers incorporate suction cup feet to keep your Hydrovescent Air Disc® secured without fear of it moving around or flipping. The 2 air diffusers have a built-in 3/8 in 90 degree elbow fitting that insures the air line connects freely to your fitting and prevents the air line from kinking at the base of the fitting. Air diffusers are great for use with EcoPlus or Commercial Air Pumps. Comes in two different sizes 4 in, 6 in.